Tuesday, 22 November 2016

Destruction of kelp forests by tropical fish shows impact of ocean temperature rises

Deforestation near Coffs Harbour coincided with 0.6C temperature rise, which had ‘catastrophic’ effect of attracting fish

Monday 14 November 2016 20.50 GMT Last modified on Tuesday 15 November 2016 01.46 GMT

Herbivorous tropical fish have destroyed kelp forests in northern New South Wales, showing that even small increases in ocean temperature can lead to kelp deforestation, an Australian study has found.

The University of NSW study, published in the Proceedings of the National Academy of Sciences on Tuesday, found that the disappearance of kelp from waters near Coffs Harbour coincided with a threefold increase in the number of tropical fish in the region.

The deforestation coincided with an 0.6 degree temperature rise. While that was not enough to directly impact the kelp, lead author Dr Adriana Vergés said it had the “truly catastrophic” effect of attracting hungry fish.

The study examined video footage of 12 sites between 2002 and 2011. In 2002, six of the sites contained kelp. By 2010, all the kelp was gone.

The proportion of kelp showing signs of bite marks increased from less than 10% in 2002 to more than 70% in 2008, before there was no kelp to measure. At the same time the proportion of tropical fish in the ecosystem increased from less than 10% to more than 30%.
Most prolific were surgeonfish, which increased from 9% of the local fish population in 2002 to 33% at the end of the study period in 2011.

Once the kelp had been removed, the ecosystem changed “quite dramatically” to become more tropical, in a trend Vergés said could potentially be seen globally.

No comments:

Post a Comment

You only need to enter your comment once! Comments will appear once they have been moderated. This is so as to stop the would-be comedian who has been spamming the comments here with inane and often offensive remarks. You know who you are!

Related Posts with Thumbnails